1. Field of the Invention
The present invention relates to a hinged-lid pack adapted for the packaging of cigarettes or filter cigarettes.
2. Description of the Related Art
Hinged-lid packs of this type are disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2-296641, for example. These conventional hinged-lid packs comprise a box-shaped body, which is open-topped. A box-shaped lid is connected to a rear opening edge of the body. The lid can be put on and removed from the open end of the body by being rocked around a self-hinge means. Thus, the lid can open and close the opening of the body.
The body has a shoulder on its front side, and the shoulder extends along the opening edge of the body. On the other hand, the lid has a flap on its front opening edge, and the flap is turned in toward the inside of the lid.
According to the hinged-lid packs described above, when the lid is put on the open end portion of the body to close the body opening, the flap of the lid is further turned in to get over the shoulder, and its distal end edge is butted against the lower end edge of the shoulder. Thus, if the lid is urged thereafter to be lifted with a relatively small force, it cannot be lifted unexpectedly, since the lid flap and the body shoulder are anchored to each other.
When the flap gets over the shoulder, it springs back to hit the front face of the body, thereby producing a click. Hearing this click, a user is expected to confirm that the lid is fully shut down and guess the freshness of the contents of the hinged-lid packs.
In the cases of the conventional hinged-lid packs described above, the distal end of the flap is kept anchored to the lower end edge of the shoulder when the lid is actually lifted, so that the flap is turned back substantially. If the open-close operation of the lid is repeated only several times, therefore, the elastic force of the basal part of the flap lowers suddenly. Thus, if the lid is shut down thereafter, the rebounding force of the flap is too feeble to produce a distinct click.
If the elastic force of the flap is reduced, the flap is left turned back and extending outside the lid. In this case, the user must deliberately tuck the flap inside the lid before shutting the lid down.
Besides this, if the flap and the shoulder fail to be disengaged satisfactorily from each other when the lid of the conventional hinged-lid packs is lifted, they are damaged inevitably as the lid is lifted forcibly. In this situation, the flap and the shoulder cannot then engage each other, so that there is the possibility of the lid being lifted unexpectedly.
In the cases of hinged-lid packs shown in FIGS. 7, 8 and 9 of the aforementioned publication, their shoulder opening portion is formed by providing the front face of their outer frame with a wide opening in a lap region between the outer frame and their inner frame so that the front face of the inner frame is exposed through the opening. With this opening in the outer frame, air flows into and out of the body of the pack through the shoulder opening portion, so that the gas barrier properties of the pack are ruined. Thus, the hinged-lid packs of this type cannot fulfill requirements for the maintenance of the freshness of cigarettes, an object of the present invention.
In a hinged-lid pack shown in FIG. 11 of the same publication. the front face of its inner frame is provided with a depressed portion. When the pack is loaded with cigarettes, however, the depressed portion cannot ensure a necessary depression for a flap of a lid, so that the lid cannot be anchored securely.
The object of the present invention is to provide a hinged-lid pack, in which a lid can be prevented from being lifted unexpectedly and can be lifted with ease when expected, the lockability of the lid can be securely maintained for a long period although the open-close operation of the lid is repeated, clicks can be produced when the lid is lifted and shut down, the clicking capability can be maintained for a long period, and the quality of cigarettes therein can be maintained satisfactorily.
The above object is achieved by a hinged-lid pack according to the present invention, which comprises a box-shaped body opening at the top end thereof, a box-shaped lid hingedly connected to a rear opening edge of the body, and locking means including a lug provided in an upper region of a front wall of the body and an engaging portion in the lid. The lid includes a front wall adapted to close the opening of the body and cover the upper region of the front wall of the body from outside when the lid is in a shut state. The lug of the locking means extends obliquely downward from the front wall of the body. The engaging portion of the locking means adjoins the distal end of the lug when the lid is shut down, and allows the distal end of the lug to be inserted temporarily into the gap between the engaging portion and the front wall of the lid when the lid in the shut state and is rocked in the opening direction.
According to the hinged-lid pack of the invention, the distal end of the lug is inserted into the gap between the front wall of the lid and the engaging portion when the lid in the shut state is rocked in the opening direction. As this is done, the lug and the engaging portion are in engagement with each other. This engagement gives a predetermined resistance to the lifting operation of the lid and causes the lid to be locked to the body. Thus, the lid cannot be lifted unexpectedly.
When the lid is lifted against the aforesaid resistance, the engaging portion of the lid raises the lug, and the lug gets out soon from between the engaging portion and the front wall of the lid. Thus, the engaging portion and the lug are disengaged from each other, whereupon the lug relatively flips the engaging portion, thereby producing a click.
When the lid is shut down, thereafter, the engaging portion of the lid flattens and clears the lug of the body. When the engaging portion is disengaged from the distal end of the lug, in this case, the lug also springs back to hit the inner surface of the lid. thereby producing a click.
Since the lug is located in the upper region of the front wall of the body, the body need not be provided with any opening. Accordingly, there is no possibility of the gas barrier properties of the hinged-lid pack being ruined. In consequence, the pack can maintain the quality of cigarettes therein for a long period.
Since the lug extends obliquely downward from the front wall of the body, moreover, the lug can satisfactorily project forward from the front wall of the body by utilizing the elastic force of its basal part even when the body is loaded with a lot of cigarettes. Thus, the engagement between the lug and the engaging portion can be obtained securely.
The front wall of the lid includes an outer wall and an inner wall lapped on the inner surface of the outer wall. The inner wall is connected integrally to the outer wall, and is turned in with respect to the outer wall. The boundary between the outer and inner walls defines a front lower edge of the lid.
The inner wall has a notch in the central portion thereof, the notch defining the engaging portion in conjunction with the front lower edge of the lid. Since the engaging portion is situated near the front lower edge of the lid, it never substantially raises the lug when the lid is lifted. In consequence, the elastic force of the basal part of the lug can be maintained for a long period. Thus, even after the open-close operation of the lid is frequently repeated, the lug can securely produce distinct clicks.
The inner wall can be lapped on the whole area of the inner surface of the outer wall. In this case, the inner wall has an opening in the central portion thereof, the opening defining the engaging portion in conjunction with the front lower edge of the lid.
The opening of the inner wall is tapered toward the ceiling of the lid. Preferably, moreover, this opening has the shape of a polygon. More specifically, the opening has the shape of a pentagon formed by cutting off both base-angle portions of an isosceles triangle having a base extending along the engaging portion. In this case, the respective tips of cigarettes cannot be positively caught by the edge of the opening even when they are repeatedly rubbed by the inner surface of the front wall of the lid as the lid is lifted and shut down. Thus, the cigarette tips cannot be easily damaged, so that the quality of the cigarettes in the pack cannot be ruined.
The length of the base of the opening of the inner wall is longer than the minimum width of the lug and shorter than the maximum width of the lug. In this case, the lug cannot be fully inserted into the gap between the engaging portion and the lid when the lid is lifted. As the lid rocks, therefore, the lug can easily get out from between the engaging portion and the lid. Thus, the lug and the engaging portion can be smoothly disengaged from each other, so that there is no possibility of the basal part of the lug tearing.
The locking means further includes a push portion attached to the lid and capable of pushing a part of the lid inward. The push of the push portion prevents the distal end of the lug from being inserted into the gap between the engaging portion and the lid when the lid in the shut state is rocked in the opening direction. More specifically, the push portion includes a substantially U-shaped slit formed in the front wall of the lid and a push piece surrounded by the slit and capable of being pushed in separately from and relatively to the front wall. In this case, the lug is depressed by the push piece to be flush with the front wall of the body when the push piece is pushed inside the lid. When the lid is rocked in the opening direction in this state, the distal end of the lug cannot be inserted into the gap between the engaging portion and the lid. Thus, the lug and the engaging portion never engage each other, so that the lid can be lifted smoothly.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.